The tricyclic compound, beta-carboline (CA Registry No. 244-63-3), is also known as norharman; carbazoline; 2-azacarbazole; 2,9-diazafluorene; and 9H-pyrido(3,4-.beta.)indole.
The preparation of certain esters of 9-pyrid(3,4-.beta.)indole alkanoic acids is described in U.S. Pat. No. 2,850,501.
U.S. Pat. No. 5,066,649 describes various 8,9-annelated 1,2,3,4-tetrahydro-beta-carbolines as orally active fibrinolytics.
Therapeutic agents for specifically reducing the production of thromboxane A.sub.2 are useful for treatment of conditions such as renal disease, (e.g., hydronephrosis, transplant rejection, and renal nephritis) pulmonary disease, (e.g., asthma, and pulmonary hypertension), prevention and treatment of hepatic and intestinal damage, cardiovascular diseases (e.g., arteriosclerosis, thrombosis, hypertension, and shock) or resulting from surgical procedures such as angioplasty and coronary bypass surgery. Aspirin has utility as a non-specific indirect inhibitor of thromboxane synthesis, however, it is desirable to discover new compounds having more potent and specific TSI properties than aspirin.